tests: check that the formulas are evaluated correctly

Author: keszybz

tests/02-zstd/etc/systemd/zram-generator.conf

@@ -5,4 +5,5 @@ set!ratio = ! echo top / bottom
 [zram0]
 compression-algorithm = zstd
 host-memory-limit = 2050
+zram-resident-limit = 9999
 zram-size = ram * ratio

tests/10-example/bin/xenstore-read

@@ -1,2 +1,2 @@
 #!/bin/sh -x
-echo 2
+echo '8 * 1024'  # MB

tests/test_cases.rs

@@ -126,6 +126,9 @@ fn test_01_basic() {
     assert_eq!(d.host_memory_limit_mb, None);
     assert_eq!(d.zram_size.as_ref().map(z_s_name), None);
     assert_eq!(d.options, "discard");
+
+    assert_eq!(d.disksize, 391 * 1024 * 1024);
+    assert_eq!(d.mem_limit, 0);
 }
 
 #[test]
@@ -136,17 +139,17 @@ fn test_02_zstd() {
     assert!(d.is_swap());
     assert_eq!(d.host_memory_limit_mb, Some(2050));
     assert_eq!(d.zram_size.as_ref().map(z_s_name), Some("ram * ratio"));
-    assert_eq!(d.disksize, 614989824);
-
     assert_eq!(
         d.compression_algorithms,
         config::Algorithms {
             compression_algorithms: vec![("zstd".into(), "".into())],
             ..Default::default()
         }
     );
-
     assert_eq!(d.options, "discard");
+
+    assert_eq!(d.disksize, 782 * 1024 * 1024 * 3 / 4);
+    assert_eq!(d.mem_limit, 9999 * 1024 * 1024);
 }
 
 #[test]
@@ -168,11 +171,17 @@ fn test_04_dropins() {
                 assert_eq!(d.host_memory_limit_mb, Some(1235));
                 assert_eq!(d.zram_size.as_ref().map(z_s_name), None);
                 assert_eq!(d.options, "discard");
+
+                assert_eq!(d.disksize, 782 * 1024 * 1024 / 2);
+                assert_eq!(d.mem_limit, 0);
             }
             "zram2" => {
                 assert_eq!(d.host_memory_limit_mb, None);
                 assert_eq!(d.zram_size.as_ref().map(z_s_name), Some("ram*0.8"));
                 assert_eq!(d.options, "");
+
+                assert_eq!(d.disksize, 782 * 1024 * 1024 * 8 / 10);
+                assert_eq!(d.mem_limit, 0);
             }
             _ => panic!("Unexpected device {}", d),
         }
@@ -321,12 +330,26 @@ fn test_10_example() {
                     }
                 );
                 assert_eq!(d.options, "");
+
+                assert_eq!(
+                    d.zram_resident_limit.as_ref().map(z_s_name),
+                    Some("maxhotplug * 3/4")
+                );
+
+                assert_eq!(d.disksize, 782 * 1024 * 1024 / 10);
+                // This is the combination of tests/10-example/bin/xenstore-read and
+                // zram-resident-limit= in tests/10-example/etc/systemd/zram-generator.conf.
+                assert_eq!(d.mem_limit, 8 * 1024 * 1024 * 1024 * 3 / 4);
             }
+
             "zram1" => {
                 assert_eq!(d.fs_type.as_ref().unwrap(), "ext2");
                 assert_eq!(d.effective_fs_type(), "ext2");
                 assert_eq!(d.zram_size.as_ref().map(z_s_name), Some("ram / 10"));
                 assert_eq!(d.options, "discard");
+
+                assert_eq!(d.disksize, 782 * 1024 * 1024 / 10);
+                assert_eq!(d.mem_limit, 0);
             }
             _ => panic!("Unexpected device {}", d),
         }

zram-generator.conf.example

@@ -31,7 +31,7 @@ zram-size = min(ram / 10, 2048)
 # then this device will not consume more than 128 MiB.
 #
 # 0 means no limit; this is the default.
-zram-resident-limit = 0
+zram-resident-limit = maxhotplug * 3/4
 
 # The compression algorithm to use for the zram device,
 # or leave unspecified to keep the kernel default.